1. Field of the Invention
The present invention relates to a switching structure or the like for operating magnification change function of driving a lens to make an observing distance variable in an endoscope.
2. Description of the Prior Art
In the endoscope, so thick a manipulative section as manually seizable is disposed at a base end side of an inserting part, while disposed at this manipulative section are an angle manipulative knob (rotational member) for bending a front end and manipulative switches such as an air/water feeding switch and a photographing switch. And, while holding the manipulative section, for example, by his left hand, a user is so arranged as to manipulate the above-described angle manipulative knob and various manipulative switches with his fingers.
Besides, it has recently been proposed to incorporate a magnification change mechanism for modifying an observation distance, for example, at an inserting front end and to drive a movable lens, constituent members of this magnification change mechanism, by means of a motor or the like. That is, this proposal lies in transmitting a rotation driving force of the above motor to the magnification change drive mechanism by using a linear transmission member, e.g., a multiple coil spring member and converting the rotary motion of the above motor into a linear motion here so as to oscillate a given movable lens back and forth, thereby actualizing a magnification change operation.
Meanwhile, a magnification change manipulative switch of such magnification change mechanism as mentioned above also is to be disposed as well as other manipulative switches at the above manipulative section, but it comes into question how they are attached to this endoscope manipulative section. That is, a switching manipulation for this magnification change is often made in relation to manipulating the above angle manipulative knob. For example, the target portion to be observed is projected out while bending the front end of an endoscope by means of the angle manipulative knob and a manipulation for magnifying or reducing this observation portion is made. Thus, such an arrangement as permitting the magnification change switch to be easily manipulated, for example, with a thumb of a user during the reciprocating travelling of this thumb is demanded between the angle manipulative knob and the magnification change knob.
Incidentally, so far, a configuration of an electric switch disposed at the endoscope manipulative section has been present as shown in Japanese Patent Laid-Open No. 6-169889.
The present invention was achieved in consideration of the above problem and its object is to provide an endoscope with the magnification change switch easily magnifiable in relation to the angle manipulative knob.
To attain the above object, an endoscope according to the present invention comprises an angle manipulative knob disposed at the manipulative section thereof for bending a front end and a magnification change manipulative switch disposed at a manipulative section of the endoscope for putting a magnification change drive unit into motion, wherein the above magnification change switch is made up of two switch bodies having individual switching functions, arranged in a direction nearly perpendicular to a rotation axis of the above angle manipulative knob and disposed nearly in contact with each other. Incidentally, the above magnification change switch can control the motion of a magnification change mechanism such as varifocal optical system for changing the observing distance or zooming optical system for making its focal length variable correspondingly.
According to the above configuration, two switching bodies are arranged in a direction nearly perpendicular to the rotation axis of the angle manipulative knob, i.e., in parallel to the rotational direction of the angle manipulative knob, and the distances of both pressing portions of these switching bodies from the angle manipulative knob become almost equal, so that a thumb of the hand holding the manipulative section is facilitated to move between the angle manipulative knob and the both pressing portions of the magnification change switch and these manipulations, (that of the angle manipulative knob conclusive), by using a thumb are smoothed.
With respect to the above magnification change switches, another invention can be configured by having the above two switch bodies retained by a single retaining member and attaching a rubber cover member to the above retaining member on which an identifiable ruggedness capable of identifying two functional operations is formed. According to this, two switch bodies are recognized as a single manipulation by means of a rubber cover member and two magnification change manipulations in a magnifying direction and in a reducing direction (direction for changing the focal length into the near or far side) can be smoothly performed on the basis of this identifiable ruggedness of the rubber cover member. Incidentally, instead of the configuration of claim 2, a rubber cover may be provided each of the above two switch bodies.
Two switch bodies of the above magnification change manipulation may comprise a switch body for manipulating the focal length toward a far direction and a switch body for manipulating the focal length toward a far direction.
Besides, with respect to the above magnification change switches, still other invention has the above switch bodies each comprising a double-step switch, in which a magnification change operation in a specified direction and the speed thereof are controlled by manipulating this individual double-step switch.
According to this other invention, both manipulating the magnification function (focal length) in near and far directions and manipulating the magnification changing speed becomes executable at one and the same manipulating position.